ABSTRACT
Mycobacterial interspersed repetitive units (MIRU) comprise short tandem repeat structures found at multiple loci throughout the Mycobacterium tuberculosis genome and have been used for typing these pathogens. We have identified MIRU at 18 conserved loci throughout the common portions of the Mycobacterium avium subspecies paratuberculosis (MAP) and M. avium subspecies avium (MAA) genomes. Six of these loci were found to differ between MAA and MAP in the number of tandem repeat motifs occurring at each MIRU locus. Locus specific PCR at 4 of these loci segregated MAP into two major groups, which could be differentiated from ovine-pigmented strains of MAP and the MAP vaccine strain 316F. The same PCR differentiated MAA into five MIRU profiles. PCR at either MIRU locus 1 or MIRU locus 4 distinguished between MAP and all other M. avium complex (MAC) tested. PCR at both loci 1 and 4 also distinguished MAP from Mycobacterium intracellulare. MIRU typing may provide an additional simple and rapid procedure for the differentiation between MAP and other MAC.
Subject(s)
DNA, Bacterial/genetics , Interspersed Repetitive Sequences , Minisatellite Repeats , Mycobacterium avium Complex/classification , Mycobacterium avium Complex/genetics , Mycobacterium avium subsp. paratuberculosis/classification , Mycobacterium avium subsp. paratuberculosis/genetics , Amino Acid Sequence , Animals , Bacterial Typing Techniques/methods , Base Sequence , Cattle , Cloning, Molecular , DNA, Bacterial/analysis , Genes, Bacterial , Humans , Molecular Sequence Data , Mycobacterium Infections/diagnosis , Mycobacterium Infections/microbiology , Mycobacterium avium/classification , Mycobacterium avium/genetics , Mycobacterium avium/isolation & purification , Mycobacterium avium Complex/isolation & purification , Mycobacterium avium subsp. paratuberculosis/isolation & purification , Polymerase Chain Reaction/methods , Rabbits , Reproducibility of Results , Sensitivity and SpecificityABSTRACT
16S rDNA sequence and pyrolysis mass spectrometric analyses were carried out on representatives of Rhodococcus equi and marker strains of genera that encompass mycolic acid containing actinomycetes. The R. equi strains formed a monophyletic clade within the evolutionary radiation occupied by members of the genera Nocardia and Rhodococcus. The 16S rDNA sequence data also showed R. equi to be an heterogeneous taxon. This heterogeneity was underscored by the pyrolysis mass spectrometric data. These observations are in line with those of previous studies where similar profiles of relatedness were found between pyrolysis mass spectral data and the results of DNA:DNA pairing and numerical phenetic studies.
